ANIMAL TISSUES. 371 



muscular fasciculus, the only diflference being, that fatty matters take 

 the place of syntonin. Now it commonly happens, that the nerve- 

 tubules terminate in stellate bodies (Plate XII., No. 10) of a precisely 

 similar nature ; and these, in this case, are supposed to possess im- 

 portant nervous functions, and go by the name of " ganglionic cells." 



The muscular fibre, known as the non-striated, or involuntary, con- 

 sists of a series of tubes presenting a flattened appearance, without the 

 transverse striiB so characteristic of the former : elongated nuclei are 

 developed immediately upon the application of a little diluted acetic acid. 

 Wharton Jones, F.R.S., first demonstrated this structure in his lectures 

 at Charing-Cross Hospital about 1843 : he was led to infer from ap- 

 pearances in very young fibre, that the striped muscular fibre is ori- 

 ginally composed of similar elements to the unstriped, or plain mus- 

 cular tissue ; which, in the process of development, become enclosed 

 in a sarcolemma (simple membrane) common to many of them : the 

 fibres then split into smaller fibres {fibriUce). Thus accounting for the 

 nuclei of striped muscular fibre ; which, according to his views, are 

 the persistent nuclei of the primitive muscular-fibre cells. 



The non-striated fibre is beautifully seen in connection with the 

 skin surrounding the hair, a few fibres of which are separately shown 

 at No. 3, Plate XIV. Professor Kolliker originally described these 

 muscles of the skin, of which there appear to be one or two in connec- 

 tion with each hair-follicle, arising from the more superficial parts of 

 the outer skin, then passing down to the root of the hair, close behind 

 the fat-gland, and there embracing it. 



It is indeed remarkable that the skin, where covered with hair, 

 should alone be provided with these muscular fibres ; the effect of the 

 contraction of which must be to thrust up the hair-follicles and depress 

 the intermediate portions of the skin, and thus produce that peculiar 

 state of the surface well known as goose-skin, a condition of the skin 

 before unaccounted for. 



Nerves. — The nervous system consists of brain, spinal marrow, and 

 nerves. There are two sets of nerves in the body ; in the one set the 

 nerves are white, firm, shining, more or less rounded, with transverse 

 markings; in the other, they are softer, not so consistent, of a reddish- 

 grey colour, and generally flat. 



Under the microscope, nerves are seen to be composed of minute 

 fibres or tubules, full of nervous matter, arranged in bundles, connected 

 by intervening fibro-cellular tissue, in which blood-vessels ramify. A 

 layer of the same, or of a delicate, transparent, structureless tissue, 

 also surrounds the whole nerve, and forms a sheath for it. The slight 



